Capacitive coupling arrangement for a faucet

ABSTRACT

A faucet includes a spout and a manual handle that controls a manual valve located in a passageway that conducts fluid flow through the spout. An electrically operable valve is also located within the passageway. The faucet also includes an insulator located between the spout and the manual handle so that the spout is electrically isolated from the manual handle, a first touch sensor on the manual valve handle, a second touch sensor on the spout, and a capacitive sensor directly coupled to one of the first and second touch sensors and capacitively coupled to the other of the first and second touch sensors. The faucet further includes a controller coupled to the capacitive sensor. The controller monitors an output signal from the capacitive sensor to detect touching of the spout and the manual valve handle. The controller is also coupled to the electrically operable valve to control the electrically operable valve in response to the output signal from the capacitive sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/600,769 filed on Nov. 18, 2009, now U.S. Pat. No. 8,613,419, which isa U.S. National Phase Application of PCT International Application No.PCT/US2008/013598, filed on Dec. 11, 2008, which claims the benefit ofU.S. Application Ser. No. 61/007,165, filed on Dec. 11, 2007, all ofwhich are expressly incorporated by reference herein.

BACKGROUND AND SUMMARY

The present invention relates to improvements in capacitive sensors foractivation of faucets. More particularly, the present invention relatesto the placement of a capacitive touch sensors in or adjacent to faucetspouts and faucet handles to sense touches by a user of the faucet andthen control the faucet based on output signals from the capacitivesensor.

An illustrated embodiment, a faucet includes a touch sensor in a spoutof the faucet, and another touch sensor in a manual valve handle. Thetouch sensor in the spout permits a user to turn water flow on and offmerely by tapping the spout. In the illustrated embodiment, the faucetdistinguishes between a tap on the spout to turn the water flow on oroff, and a longer grasping or grab of the spout, for example, to swingit from one basin of a sink to another. The faucet therefore provides aneasy and convenient way to turn the water off and on without having toadjust the water flow rate and temperature.

The touch sensor in the handle can also be used for a tap control, whichdistinguishes between grasping or grab of the handle to adjust the waterflow rate or temperature, and merely tapping the handle to toggle waterflow off or on. The touch sensor in the handle provides an additionalsource of input data for the faucet which permits the faucet to moreaccurately determine the intent of the user, thereby providing greaterwater savings while being intuitive and easy to use.

According to an illustrated embodiment of the present disclosure, afaucet comprises a spout, a passageway that conducts fluid flow throughthe spout, a electrically operable valve located within the passageway,a manual valve located within the passageway in series with theelectrically operable valve, and a manual handle that controls themanual valve. The faucet also comprises a first touch sensor on themanual valve handle, a second touch sensor on the spout, a capacitivesensor directly coupled to one of the first and second touch sensors andcapacitively coupled to the other of the first and second touch sensors,and a controller coupled to the capacitive sensor. The capacitive sensorprovides an output signal. The controller is configured to monitor theoutput signal from the capacitive sensor and to distinguish between auser tapping one of the spout and the manual valve handle, a usergrabbing the spout, and a user grabbing the manual valve handle. Thecontroller is also coupled to the electrically operable valve to controlthe electrically operable valve is response to the output signal fromthe capacitive sensor.

According to another illustrated embodiment of the present disclosure, amethod is provided for controlling fluid flow in a faucet having aspout, a passageway that conducts fluid flow through the spout, aelectrically operable valve located within the passageway, a manualvalve located within the passageway in series with the electricallyoperable valve, and a manual handle that controls the manual valve. Themethod comprises providing a first touch sensor on the manual valvehandle, providing a second touch sensor on the spout, providing acapacitive sensor, directly coupling one of the first and second touchsensors to the capacitive sensor, capacitively coupling the other of thefirst and second touch sensors to the same capacitive sensor, monitoringan output signal from the capacitive sensor to detect touches of boththe first and second touch sensors by a user, and controlling theelectrically operable valve is response to the monitoring step.

Additional features and advantages of the present invention will becomeapparent to those skilled in the art upon consideration of the followingdetailed description of illustrative embodiments exemplifying the bestmode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the drawings particularly refers to theaccompanying figures in which:

FIG. 1 is a block diagram of a fluid delivery assembly including acapacitive sensor system;

FIG. 2 is an example of a dual-electrode, capacitively coupled sensingsystem with a single capacitive sensor;

FIG. 3 is a block diagram illustrating a spout of a fluid deliveryassembly capacitively coupled to a faucet body hub by an insulator;

FIG. 4 illustrates a signal amplitude output in response to short tapsand longer grabs on the first and second electrodes of FIGS. 1 and 2;

FIG. 5 is a flow chart illustrating steps performed by a controller todistinguish between short taps and longer grabs on the first and secondelectrodes of a capacitive sensor system of FIGS. 1 and 2; and

FIG. 6 is an operation state diagram illustrating control of fluid flowbased on an output of the capacitive sensor.

DETAILED DESCRIPTION OF THE DRAWINGS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to certain illustrated embodimentsand specific language will be used to describe the same. It willnevertheless be understood that no limitation of the scope of theinvention is thereby intended. Such alterations and furthermodifications of the invention, and such further applications of theprinciples of the invention as described herein as would normally occurto one skilled in the art to which the invention pertains, arecontemplated and desired to be protected.

FIG. 1 is a block diagram illustrating one embodiment of a sensingfaucet system 10 of the present invention. The system 10 includes aspout 12 for delivering fluid such as water into a sink basin, forexample, and at least one manual valve handle 14 for controlling theflow of water through the spout 12 in a manual mode. A hot water source16 and cold water source 18 are illustratively coupled to a manual valvebody assembly 20. In one illustrated embodiment, separate manual valvehandles 14 are provided for the hot and cold water sources 16, 18. Inanother illustrated embodiment, such as for a kitchen application, asingle manual valve handle 14 is used for both hot and cold waterdelivery. In such kitchen embodiment, the manual valve handle 14 andspout 12 are typically coupled to the basin through a single hole mount.An output of valve body assembly 20 is coupled to an actuator drivenvalve 22 which is controlled electronically by input signals from acontroller 24. Valves 20 and 22 are illustratively located in apassageway that conducts fluid flow through the spout 12. In anillustrative embodiment, actuator driven valve 22 may be a magneticallylatching pilot-controlled solenoid valve.

In an alternative embodiment, the hot water source 16 and cold watersource 18 may be connected directly to actuator driven valve 22 toprovide a fully automatic faucet without any manual controls. In yetanother embodiment, the controller 24 controls an electronicproportioning valve (not shown) to supply water for the spout 12 fromhot and cold water sources 16, 18.

Because the actuator driven valve 22 is controlled electronically bycontroller 24, flow of water can be controlled using outputs from acapacitive sensor 30 as discussed herein. As shown in FIG. 1, when theactuator driven valve 22 is open, the faucet system may be operated in amanual control mode through operation of the handle(s) 14 and the manualvalve member of valve body assembly 20. Conversely, when the manuallycontrolled valve body assembly 20 is set to select a water temperatureand flow rate, the actuator driven valve 22 can be touch controlled whena user's hands touch a sensor to toggle water flow on and off asdiscussed below.

A first touch sensor electrode 26 is electrically coupled to the manualvalve handle(s) 14. Spout 12 illustratively has a second touch sensorelectrode 28 capacitively coupled to the first electrode 26. The spout12 is illustratively made from a conductive material to form the secondtouch sensor electrode 28. Alternatively, a separate electrode 28 may becoupled to the spout 12.

First electrode 26 is directly coupled to the capacitive sensor 30 ofcontroller 24. In the embodiment of FIG. 1, a wire is used to connectthe first electrode 26 to the capacitive sensor 30. It is understoodthat any conventional capacitive sensor 30 may be used in accordancewith the present invention. See, for example, U.S. Pat. No. 6,962,168which is incorporated herein by reference. Since the spout 12 is oftenmovable, it is not desirable to have a wire connection to the electrode28 of spout 12. Therefore, the electrode 28 of spout 12 is capacitivelycoupled to the electrode 26 as discussed in more detail below. It isunderstood that in another embodiment, the second electrode 28 on thespout 12 may be directly coupled to the capacitive sensor 30 and thefirst electrode 26 on the handle 14 may be capacitively coupled to thefirst electrode 28.

FIG. 2 is an example of a dual electrode, capacitively coupled sensingarrangement using a single capacitive sensor 30. Although the embodimentof FIG. 2 is specifically disclosed herein for use with a fluid deliveryapparatus such as a faucet, it is understood that the sensing andcontrol techniques used herein may have other applications.

FIG. 3 illustrates additional details of a single hole mount faucet 31.A faucet body hub 32 is electrically coupled to the manual valve handle14, for example, by metal-to-metal contact between the handle 14 and thehub 32. Manual valve handle 14 is movably coupled to the faucet body hub32 in a conventional manner to control water flow and temperaturethrough valve 20. Since the manual valve handle 14 and the faucet bodyhub 32 are electrically connected, the first electrode 26 may be coupledto either the manual valve handle 14 or the hub 32, as desired.

The spout 12 is coupled to faucet body hub 32 by an insulator 34. In oneembodiment, such as for a kitchen faucet, the spout 12 is rotatablerelative to the faucet body hub 32. In other embodiments, the spout 12may be fixed relative to the faucet body hub 32. Spout 12 may include apull-out or pull-down spray head which is electrically isolated from thespout 12.

As discussed above, the manual valve handle 14 is electrically connectedto the faucet body hub 32. The spout 12 is capacitively coupled to thebody hub by insulator 34. When the manual valve handle 14 is touched bya user's hand, the capacitance to earth ground is directly coupled. Thecapacitive sensor 30 of controller 24 therefore detects a largercapacitance difference when the handle 14 is touched by a user comparedto when the spout 12 is touched. This results in a larger amplitudeoutput signal when the manual valve handle 14 is touched by a user'shand compared to when the spout 12 is touched. By comparing theamplitude of the output signal to predetermined threshold values, thecontroller 24 can detect where the faucet is touched and how long thefaucet is touched to enable the controller 24 to make water activationdecisions as discussed below.

The following is a description of algorithms used to process “touch”conditions of two electrodes 26, 28 which are capacitively coupled toone another using a single capacitive sensor 30 which detects changes inelectrical capacitance. The interpretation of how and when theelectrodes 26, 28 are touched is used to determine when to actuate anelectronic valve 22.

It should be appreciated that the method and apparatus detailed hereinmay be used in connection with the faucet disclosed in PCT InternationalPatent Application Publication No. WO 2008/088534 entitled “MULTI-MODEHANDS FREE AUTOMATIC FAUCET”, filed Dec. 11, 2007, and U.S. patentapplication Ser. No. 11/641,574, filed Dec. 29, 2006, and published asU.S. Publication No. 2007/0157978, the disclosures of which areexpressly incorporated by reference herein.

A first embodiment of a detection algorithm for distinguishing betweenshort taps and longer grabs of the spout 12 or handle 14, for example,will be described first. The following definitions are used in the firstexample of the detection algorithm. A “tap” is a touch of short durationdesigned to turn the water or fluid on or off. A “grab” has a longerduration such as when a user grasps the spout 12 to move the spout fromone area of the sink basin to another or when the user grasps the manualvalve handle 14 to adjust the flow rate or temperature of the fluid. Thefollowing definitions apply to the first embodiment. Taps and grabs aredetermined differently in the second embodiment discussed below.

-   -   Slew Rate: The maximum rate of change of an output signal,        expressed in units/second. (Example: counts/second,        volts/second, LSbs/second)    -   Direct Coupling: the connection of an electrode that is        resistively coupled, or connected, to the input of a sensor.    -   Capacitive Coupling: an electrode's connection to the input of a        sensor which is capacitive in nature due to a physical        separation by some material with a defined dielectric constant.        There is no resistive element in the connection in this type of        configuration.    -   Tap: an event which occurs when a sensor's output signal crosses        above the absolute value of a pre-defined threshold for some        period, t_(R), and the following condition is met: T_(TAP) _(—)        _(MIN≦t) _(R)<T_(TAP) _(—) _(MAX).    -   Grab: An event which occurs any time a sensor's output signal        crosses above the absolute value of a pre-defined threshold for        at least T_(TAP) _(—) _(MAX).    -   Touch: An event which is defined as any time a sensor's output        signal crosses above the absolute value of a pre-defined        threshold for at least T_(TAP) _(—) _(MIN).    -   Release: An event which is defined as any time a sensor's output        signal crosses below the absolute value of a pre-defined        threshold.    -   T_(TAP) _(—) _(MIN): A defined, minimum, amount of time which a        sensor's output signal must cross above the absolute value of a        pre-defined threshold to qualify as a tap condition.    -   T_(TAP) _(—) _(MAX): A defined, maximum, amount of time which a        sensor's output signal must crosses above the absolute value of        a pre-defined threshold to qualify as a tap condition. The        signal must have dropped below the threshold prior to this time        to still qualify as a tap condition. If the signal is still        above the threshold beyond this period of time, a grab condition        has occurred.

FIG. 4 illustrates a typical output response signal of a dual electrode26, 28, capacitively coupled sensing arrangement using a singlecapacitive sensor 30 as discussed above. The distinction between humantouches on each electrode 26, 28 can be seen in FIG. 4. Possiblealgorithm threshold settings are shown on the graph of FIG. 4. Forexample, FIG. 4 illustrates a lower threshold amplitude at line 80, amiddle threshold amplitude at line 82, and an upper threshold amplitudeillustrated at line 84.

Due to the slew rate of a chosen sensor connected to a particularelectrode, it will take some minimum amount of time for the outputsignal to reach its maximum amplitude and achieve some steady statelevel. This is shown in FIG. 4 in which the directly coupled firstelectrode 26 is tapped at location 90, and the maximum output level ofthe sensor is less than the maximum output level achievable if the firstelectrode 26 is grabbed for a minimum amount of time to allow a steadystate level to be reached as illustrated at location 92. The slew ratefor a directly coupled electrode 26 and a capacitively coupled electrode28 may differ. The maximum achievable amplitude of a capacitivelycoupled electrode 28 is less than the maximum achievable amplitude of adirectly coupled electrode 26. For example, location 86 of FIG. 4illustrates the amplitude of the signal when capacitively coupledelectrode 28 is tapped and location 88 illustrates the maximumachievable amplitude of the capacitively coupled electrode 28 when theelectrode 28 is grabbed to allow a steady state level to be reached. Themaximum steady state level achievable by a given sensor in a givensystem may vary depending on the following conditions:

1. What, or who, is touching the sensor,

2. The particular type of capacitive sensing technology employed by thesystem,

3. The amount of capacitance between the two electrodes and theassociated dielectric constant of the material of separation,

4. Any conductive materials in the near vicinity of the electrodes whichmay add to the total capacitance being sensed.

In a system using two separate sensors for the two electrodes withisolation between the electrodes, distinguishing between taps, grabs,and releases of the two electrodes is a fairly straight forward task.However, due to the behavior of a system using capacitively coupledelectrodes 26, 28 and a single capacitive sensor 30 as shown in FIGS. 1and 2, the manner in which detections are made differs. Tables 1 through3 show the possible detection states that can be accurately determinedusing the different sensing configurations.

As shown in Table 1, a dual sensor, dual electrode configuration canaccurately distinguish up to 16 different states. A drawback is that thecontrol algorithms must also process and determine what state iscurrently present. Table 2 shows what states are possible to determineusing a single sensor, dual electrode configuration with capacitivelycoupled electrodes as shown in FIGS. 1 and 2, for example.

TABLE 1 Electrode 1 Electrode 2 STATE TOUCHED TAPPED GRABBED TOUCHEDTAPPED GRABBED 1 0 0 0 0 0 0 2 0 0 0 0 1 0 3 0 0 0 1 0 0 4 0 0 0 1 0 1 50 1 0 0 0 0 6 0 1 0 0 1 0 7 0 1 0 1 0 0 8 0 1 0 1 0 1 9 1 0 0 0 0 0 10 10 0 0 1 0 11 1 0 0 1 0 0 12 1 0 0 1 0 1 13 1 0 1 0 0 0 14 1 0 1 0 1 0 151 0 1 1 0 0 16 1 0 1 1 0 1

Detectable states using a dual sensor, dual electrode sensingconfiguration

TABLE 2 Electrode 1 (Direct) Electrode 2 (Capacitive) TOUCHED TAPPEDGRABBED TOUCHED TAPPED GRABBED STATE 0 0 0 0 0 0 1 0 0 0 0 1 0 2 0 0 0 10 0 3 0 0 0 1 0 1 4 0 1 0 0 0 0 5 1 0 0 0 0 0 6 1 0 1 0 0 0 7

Detectable states using a single sensor configuration with capacitivelycoupled electrodes

TABLE 3 E1 TOUCH E2 TOUCH TAPPED GRABBED STATE 0 0 0 0 1 0 0 1 0 2 0 1 00 3 0 1 0 1 4 1 0 0 0 5 1 0 0 1 6

Shown is a further reduction of states in Table 2 by eliminating theneed to detect a tap of electrode 1 and electrode 2 separately.

For the example shown in Table 1, thresholds for each sensor/electrodecan be determined such that at any time the sensor's signal crosses saidthreshold, the electrode is defined as having been touched. If thesignal crosses the threshold for a defined period of time, as defined inthe Definitions section above, flags can be set as to whether theelectrode has been tapped or grabbed. The exact states that appear forone electrode in this example can appear for the second electrode at thesame time. In this configuration, each sensor can have its own set ofthresholds for determining when the sensor has been touched andreleased. The setting of those thresholds can be determined using a“dynamic baseline” determined from the raw sensor signal. A dynamicbaseline is a calculated level based on the raw output level of thesensor. In this way, the “baseline” will tend to track the raw signal inthe manner defined by the calculation of the baseline. Havingindependent thresholds is not possible for the case of a single sensorapplication using capacitively coupled electrodes.

Table 2 describes the detectable states that can be determined in theapplication shown in FIGS. 1 and 2. FIG. 4 illustrates that if electrode28 is touched for a long enough time to reach steady state amplitude,that the maximum achievable level at location 88 is not as great as themaximum achievable amplitude of electrode 26 which is directly coupledto the capacitive sensor 30 as illustrated at location 92. If the UpperThreshold 84 shown in FIG. 4 is adjusted such that it is above themaximum amplitude of electrode 28, but below the maximum amplitude ofelectrode 26, a determination can be made between the two. However, dueto the rise times associated with each electrode's slew rate, a tapevent on the first electrode 26 may never cross the Upper Threshold 84as illustrated at location 90 and cannot be reliably distinguishedbetween a tap of electrode 28 and a tap of electrode 26. For thisreason, the algorithm may be designed using a reduced subset of statesshown in Table 2 as reflected in Table 3.

An example for this type of sensing is in the control of the electronicvalve 22 for a plumbing application. The algorithm in question will dothe following:

1. If the first electrode 26 (directly coupled electrode) is touched andthe Electronic Valve 22 (from here on referred to as the EV,) is closed,the request will be made to open the EV 22.

2. If either electrode 26, 28 is tapped while the EV 22 is open, arequest will be made to close the EV 22.

3. If first electrode 26 is grabbed and the EV 22 is open, no actionwill be taken on the EV 22.

4. If second electrode 28 is grabbed and the EV 22 is open, no actionwill be taken on the EV 22.

5. If second electrode 28 is grabbed and the EV 22 is closed, no actionwill be taken on the EV 22.

6. If either electrode 26, 28 is tapped while the EV 22 is closed, arequest will be made to open the EV 22.

Instead of trying to determine the difference between two electrodes 26,28, rather, we concentrate on determining whether the sensor's signalhas crossed one of three dynamic thresholds 80, 82, 84 as shown in FIG.4. Therefore, one more step in the algorithm needed for detecting thestates of Table 2 may be saved to go from 7 possible states to 6. Thealgorithm will then obey the following rules: (Sensor's Signal=SIG,UT=Upper Threshold, MT=Middle Threshold and LT=Lower Threshold.)

1. If |SIG|>|UT| for a period t_(R), and t_(R)≧T_(TAP) _(—) _(MIN), andthe EV is closed, a request will be made to open the EV. This isreflected by states 5 and 6 of Table 3.

2. |SIG|>|MT| for a period t_(R), has been released, and T_(TAP) _(—)_(MIN)≦t_(R)<T_(TAP) _(—) _(MAX), a request will be made to close the EVif it was previously open, or open the EV if it was previously closed.This is reflected by state 2 of Table 3.

3. |SIG|>|MT| for a period t_(R), the EV is open, and t_(R)≧T_(TAP) _(—)_(MAX), no action is taken.

This is reflected by states 4 and 5 of Table 3.

4. |SIG|<|MT|, no action is taken, regardless of the state of the EV.

State Tables

TABLE 4 Timer State Timer Enabled t_(R) 0 1 t_(R) < t_(MIN) 1 1 t_(MIN)≦ t_(R) < t_(MAX) 2 1 t_(MAX) ≦ t_(R) 3 0 t_(R) = 0

TABLE 5 EV State EV 0 Closed 1 Open

TABLE 6 |SIG| State Signal Active |SIG| 0 1 |SIG| ≦ |MT| 1 1 |MT| <|SIG| ≦ |UT| 2 1 |UT| < |SIG| 3 0 |SIG| ≦ |MT| 4 0 |MT| < |SIG| ≦ |UT| 50 |UT| < |SIG|

TABLE 7 EV State |SIG| State Timer State Action 0 0 0 0 1 1 2 2 3 0 1 00 1 0 2 3 3 4 2 0 0 1 5 2 5 3 4 3 NA 7 4 NA 0 5 NA 0 1 0 0 0 1 6 2 2 3 01 0 0 1 0 2 3 3 4 2 0 0 1 0 2 3 3 4 3 NA 7 4 NA 0 5 NA 0

TABLE 8 Action Description 0 No Action 1 OPEN EV, Disable Timer, t_(R) =0 2 Disable Timer, t_(R) = 0 3 Signal = Inactive, Disable Timer, t_(R) =0 4 Enable Timer 5 OPEN EV, Disable Timer, t_(R) = 0, Signal = Inactive6 CLOSE EV, Disable Timer, t_(R) = 0 7 Signal = Active

Process Flow

1. The states in Table 4 are defined based on the current value of t_(R)and whether or not the timer is enabled.

2. The EV State, as shown in Table 5 is defined when a change of the EVstate is made.

3. The |SIG| State in Table 6 is adjusted based on the current value ofthe sensor signal in relation to the defined threshold levels, MT andUT. States 0 through 2 are for when the signal is defined as being“active,” and states 3 through 5 are for when the signal is defined asbeing “inactive.”

4. Table 8 is a listing of possible actions to be taken based on theconditions shown in Table 7.

5. Table 7 shows the various actions to be taken depending on the statesof the EV, |SIG| State, and Timer State.

In another illustrated embodiment of the present invention, an algorithmis provided which detects a tap by a user on either the first or secondelectrodes 26, 28 based upon a change in a slope detected at a leadingedge of the output signal from the capacitive sensor 30. FIG. 5 is aflow chart illustrating the steps performed by controller 24 to monitorthe output of the capacitive sensor 30 and determine when the electrodes26, 28 are tapped or grabbed for controlling the fluid flow.

The process starts at block 40. Initially no tabs or grabs are detectedas illustrated at block 42. Controller 24 inputs sensor data from thecapacitive sensor 30 as illustrated at block 44. Controller 24 thendetermines whether a positive slope of the output signal is detected atblock 46. Leading edges of each of the touches at locations 86, 88, 90and 92 in FIG. 4, for example, are detected as a positive slopeoccurrences. The detected slope must be large enough to distinguish itfrom a gradual amplitude increase, such as when a user's hands approachthe faucet, as illustrated at location 94 in FIG. 4, for example. In anillustrated embodiment, the slope must increase for about 10 counts inorder for a positive slope to be detected at block 46.

If a positive slope is not detected at block 46, controller 24 returnsto block 44 to input additional sensor data. If a positive slope isdetected at block 46, controller 24 determines whether or not thepositive slope is caused by an electromagnetic interference (EMI) eventat block 48. For example, electromagnetic interference may occur ifsomeone starts a dishwasher or other appliance near the faucet.Controller 24 may test for an EMI event by confirming that the positiveslope still exists at a later time interval such as, for example, 10 msafter the positive slope is initially detected. If the signal is stillhas a positive slope after 10 ms, controller 24 determines that thepositive slope is caused by a touch of electrodes 26 or 28 and not by anEMI event.

If an EMI event is detected at block 48, controller 24 returns to block44 to input additional sensor data. If an EMI event is not detected atblock 48, controller 24 inputs additional sensor data at block 50.Controller 24 then determines whether a negative slope of the outputsignal is detected at block 52. Negative slopes of the output signal areillustrated, for example, at the trailing edges of portions 86, 88, 90and 92 of the output signal of FIG. 4. If a negative slope is detectedat block 52, controller 24 determines that a “tap” has been detected asillustrated at block 54. Controller 24 will then control the electronicvalve 22 as discussed below in response to the tap. Controller 24 thenreturns back to the start block 40 to monitor for the next touch ofelectrodes 26, 28.

If a negative slope is not detected at block 52, controller 24determines whether an elapsed time since the positive slope was detectedat block 46 is less than a maximum elapsed time permitted for a tapevent as illustrated at block 56. Illustratively, the maximum elapsedtime for a tap event is about 300 ms. If the elapsed time is less thanthe maximum time for a tap event, controller 24 returns to block 50 toinput additional sensor data. If the elapsed time at block 56 exceedsthe maximum time permitted for a tap event at block 56, controller 24detects a “grab” as illustrated at block 58. Next, controller 24determines a type of grab that has occurred as illustrated at block 60.In the illustrated example, controller 24 distinguishes between a“strong” grab at block 62 and a “weak” grab at block 64. A strong grabat block 62 occurs when the user grabs the manual valve handle 14 usedto adjust the flow or temperature of the fluid. A weak grab at block 64occurs when the user grabs the spout 12. Controller 24 will then controlthe electronic valve 22 as discussed below in response to the detectedstrong or weak grab.

Once a determination is made between a strong grab and a weak grab,controller 24 sets a timer for grab release window values as illustratedat block 66. Controller 24 then inputs additional sensor data asillustrated at block 68. Next, controller 24 determines whether a grabrelease is detected within the release window at block 70. If not,controller 24 continues to input sensor data at block 68. If the grabrelease is detected at block 70, controller 24 returns back to startblock 40 to monitor for the next touch of electrodes 26, 28. A grabrelease is detected by a negative slope of the output signal indicatingthat the user has released the electrode 26, 28.

In the embodiment of FIG. 5, the output from the capacitive sensor 30does not have to reach a lower threshold level such as level 80 in FIG.4 in order to be considered a tap event. Therefore, the embodiment ofFIG. 5 provides improved detection of taps of the electrodes 26, 28.When the electrodes 26, 28 are grabbed for a longer period of time, thesteady state amplitudes are reached at, for example, locations 88 and 92of FIG. 4. These steady state levels are more easily predicted than theshorter duration taps as discussed above. In the embodiment of FIG. 5,the upper threshold level 84 is set to distinguished between stronggrabs of the first electrode 26 on the handle 14 and weak grabs of thesecond electrode 28 on the spout 12. Once a grab is detected, if theamplitude of the steady state signal at location 88 is detected, it isdetermined that a grab of the spout 12 has occurred since the amplitudeis below the upper threshold 84. If the output signal is above the upperthreshold 84 during a grab as indicated at location 92, a strong grab ofthe handle 14 is detected.

The maximum amplitudes of the steady state signals when the first andsecond electrodes 26, 28 are grabbed at locations 92 and 88,respectively, of FIG. 4 may be adjusted. For example, the hub 32 mayinclude a metallic portion which extends into the insulator 34. Themetallic portion of the hub 32 overlaps a portion of the metal spout 12.The amount of overlap of metal between the hub 32 and the spout 12effects the signal amplitude of the output signal of capacitivelycoupled electrode 26. Therefore, by reducing the metallic overlapbetween the hub 32 and the spout 12, the signal amplitude 88 in responseto touches of the second electrode 28 coupled to the spout 12 may bereduced. Increasing the signal amplitude difference between the maximumsignal output of the first and second electrodes 26, 28, facilitatesdistinguishing between strong grabs of the manual valve handle 14 andweak grabs of the spout 12.

FIG. 6 is an operation state diagram for the second embodiment of thepresent invention. If the water is off, a tap of either the handle lever14 or spout 12 will cause the water to turn on. A strong grab indicatingthat the handle 14 is grabbed will also turn the water on. However, whenthe water is off, a weak grab of the spout 12 will not turn on thewater. When the water is on, a tap of the lever handle 14 or spout 12will turn the water off However, when the water is on, strong and weakgrabs of the handle 14 and spout 12 respectively, will not cause thewater to turn off. Therefore, when the water is on, the user can adjustthe location of the spout or grab the handle 14 and adjust thetemperature or flow rate of the water without shutting the water off.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the description is to be consideredas illustrative and not restrictive in character. Only illustratedembodiments, and such alternative embodiments deemed helpful in furtherilluminating the illustrated embodiments, have been shown and described.It will be appreciated that changes and modifications to the forgoingcan be made without departing from the scope of the following claims.

1. A faucet comprising: a spout; a passageway that conducts fluid flowthrough the spout; an electrically operable valve located within thepassageway; a manual valve located within the passageway in series withthe electrically operable valve; a manual handle that controls themanual valve; an insulator located between the spout and the manualhandle so that the spout is electrically isolated from the manualhandle; a first touch sensor on the manual valve handle; a second touchsensor on the spout; a capacitive sensor directly coupled to one of thefirst and second touch sensors and capacitively coupled to the other ofthe first and second touch sensors without a direct electricalconnection through a conductor to the capacitive sensor, the capacitivesensor providing an output signal; and a controller coupled to thecapacitive sensor, the controller being configured to monitor the outputsignal from the capacitive sensor to detect touching of the spout andthe manual valve handle, the controller also being coupled to theelectrically operable valve to control the electrically operable valvein response to the output signal from the capacitive sensor.
 2. Thefaucet of claim 1, wherein the controller toggles the electricallyoperable valve between open and closed positions in response todetecting a user tapping one of the spout and the manual valve handle.3. The faucet of claim 1, wherein the controller toggles theelectrically operable valve when either of the first and second touchsensors are touched and released within a period of time shorter than apredetermined time.
 4. The faucet of claim 1, wherein the electricallyoperable valve is a magnetically latching valve.
 5. The faucet of claim1, wherein the controller determines that a user has tapped one of thespout and the manual valve handle when both a positive slope of theoutput signal and a negative slope of the output signal are detectedwithin a predetermined period of time.
 6. The faucet of claim 5, whereinthe controller further determines whether an electromagnetic eventcaused the positive slope of the output signal instead of a tap by theuser on the spout or the manual valve handle.
 7. The faucet of claim 5,wherein the controller further determines that a user has grabbed one ofthe spout and the manual valve handle when the length of time betweenthe positive slope of the output signal and the negative slope of theoutput signal is greater than the predetermined time.
 8. The faucet ofclaim 7, wherein, if the controller determines that one of the spout andmanual valve handle was grabbed by a user, the controller furtherdetermines which one of the spout and manual valve handle was grabbed bya user based upon an amplitude of the output signal between the detectedpositive and negative slopes.
 9. The faucet of claim 8, wherein thecontroller determines that the manual valve handle was grabbed by a userif the amplitude of output signal between the detected positive andnegative slopes is greater than a predetermined threshold value.
 10. Thefaucet of claim 9, wherein the controller determines that the spout wasgrabbed by a user if the amplitude of the output signal between thedetected positive and negative slopes is less than the predeterminedthreshold value.
 11. The faucet of claim 1, wherein the electricallyoperable valve is an electronic proportioning valve and wherein thecontroller directs the electrically operable valve to change among open,closed, and the plurality of partially closed positions in response to aduration of contact by the user with the first and second touchcontrols.
 12. The faucet of claim 1, further comprising a faucet bodyhub, the manual valve handle being movably coupled to the faucet bodyhub to control the manual valve, the manual valve handle beingelectrically coupled to the faucet body hub, and wherein the spout iscoupled to the faucet body hub by the insulator so that the spout iselectrically isolated from the faucet body hub.
 13. The faucet of claim12, wherein the spout is rotatably coupled to the faucet body hub. 14.The faucet of claim 1, wherein the first touch sensor includes a firstelectrode coupled to the manual valve handle, the first electrode beingdirectly coupled to the capacitive sensor.
 15. The faucet of claim 14,wherein the second touch sensor includes a second electrode on thespout, the second electrode being capacitively coupled to the firstelectrode.
 16. The faucet of claim 15, wherein the spout is formed froma conductive material to provide the second electrode.
 17. The faucet ofclaim 1, wherein the controller is configured to monitor the outputsignal from the capacitive sensor and to distinguish between a usertapping one of the spout and the manual valve handle, a user grabbingthe spout, and a user grabbing the manual valve handle, and wherein thecontroller controls the electrically operable valve in response to theoutput signal from the capacitive sensor as follows: if either of thefirst and second touch sensors are tapped while the electricallyoperable valve is closed, the controller opens the electrically operablevalve; if the first touch sensor is grabbed and the electricallyoperable valve is closed, the controller opens the electrically operablevalve; if either of the first and second touch sensors are tapped whilethe electrically operable valve is open, the controller closes theelectrically operable valve; if first touch sensor is grabbed and theelectrically operable valve is open, no action is taken on theelectrically operable valve; if second touch sensor is grabbed and theelectrically operable valve is open, no action is taken on theelectrically operable valve; and if second touch sensor is grabbed andthe electrically operable valve is closed, no action is taken on theelectrically operable valve.